PRODUCT DATA

Put UPC Code Here
60-2152—08
L91A,B,D ProportioningPressuretrol® Controllers

APPLICATION

L91 Proportioning Pressuretrol® Controllers are Series 90
Modulating Pressure Controllers that provide direct control of
modulating motors or valves used on automatic burners or
steam heating systems.

FEATURES

Models available for pressure systems up to 300 psi
(2068 kPa).
May be used with steam, air, noncombustible gases, or
other fluids noncorrosive to brass or phos-bronze (300
psi model) bellows.
When used with steam boilers, a steam trap (siphon
loop) is recommended.
Wiper on controller potentiometer moves in response
to pressure changes.
L91D has two potentiometers for unison control of two
motors.
L91B,D models have adjustable proportioning
(throttling) range to allow selection of desired
pressure control range.
Adjustments made with screws on case top.
Large, easily-read scaleplates in both U.S. customary
(oz/sq. in., psi, or in. Hg) and metric (kPa, MPa, or mm
Hg) units.
Steel case with clear plastic cover to observe pressure
settings and potentiometer action.
Fitting with 1/4 -18 NPT threads allows rapid
installation.
Surface mount with screws through knockout holes in
case back.

Contents

Application 1
Features 1
Specifications 2
Installation 5
Wiring 6
Checkout 8
Service Information 9